Fuel injection devices

ABSTRACT

A fuel injection device includes means whereby a rotating flow of an air/fuel mixture is sandwiched between rotating internal and external air flows. The components of the device are grouped into separately mounted sub-assemblies which are movable slidably relative to one another.

United States Patent [1 1 Caruel et al.

FUEL INJECTION DEVICES Inventors: Jacques Emile Jules Caruel,

Dammarie-les-Lys; Jean Robert Be'due', Creteil; Jean Alfred EugneCharles Dobigny, Le Mee-sur-Seine; Roland Robert Charles Beyler,Levallois-Perret; Michel Bernard Schenher, Paris, all of France SocieteNationale dEtude et de Construction de Moteurs dAviation, Paris, FranceFiled: June 27, 1974 Appl. N0.: 483,573

Assignee:

Foreign Application Priority Data Oct. 28, 1975 [56] References CitedUNITED STATES PATENTS 1,881,359 10/1932 Jones 239/400 2,612,405 9/1952Kirschbaum 239/404 2,701,164 2/1955 Purchas, Jr. et a]. 3,039,701 6/1962carlisle 3,612,737 10/1971 Sharan 239/404 Primary Examiner-Lloyd L. KingAttorney, Agent, or FirmWilliam J. Daniel [57] ABSTRACT A fuel injectiondevice includes means whereby a rotating flow of an air/fuel mixture issandwiched between rotating intemal and external air flows. Thecomponents of the device are grouped into separately mountedsub-assemblies which are movable slidably relative to one another.

7 Claims, 4 Drawing Figures US. Patent Oct.28, 1975 Sheet 1 of33,915,387

US. Patent Oct. 28, 1975 Sheet 2 of3 3,915,387

Sheet 3 of 3 3,915,387

' US. Patent Oct. 28, 1975 {WME 6 ,2 2 i 2 4 M ml 4 M FUEL INJECTIONDEVICES This invention relates to a high-performance fuel injectiondevice designed particularly for aircraft jet propulsion systems and inwhich an intermediate annular flow containing fuel is sandwiched betweeninternal and external flows of air caused to rotate by means of innerand outer bladed elements which are normally referred to as swirlers.

According to the invention, this intermediate annular flow comprises amixture of air and fuel and is itself caused to rotate by a third bladedelement, for example a swirler having helical blades and the componentsof the device are grouped into two sub-assemblies which are movableslidably relative to one another and are fixed separately to differentparts of a fixed structure such as the jet engine combustion chamber.

In a fuel injection device in accordance with the invention the shearingeffect which the internal and external flows of air exert on thesandwiched intermediate flow of fuel and air can be increased by givingdifferent rotational angular settings to the vanes or blades of theinternal and external swirlers, the external blades having preferably asmaller angular setting than the internal blades.

Relative sliding movement between the two subassemblies takes placepreferably adjacent the swirler which serves to produce rotation of theexternal flow of air. To this end, a slidable sleeve is located at theinner periphery of the external swirler.

The invention will now be described by way of example with reference toone embodiment of fuel injection device which is illustrated in theaccompanying drawings.

In the drawings:

FIGS. 1 and 2 are transverse and longitudinal crosssectional viewsshowing the elements of the fuel injection device, FIG. 1 being asection along the line II of FIG. 2 and the latter being a section alongthe line IIII of FIG. 1,

FIG. 3 is an exploded schematic view of the device shown in FIGS. 1 and2, and 4 FIG. 4 is a longitudinal sectional view of a device accordingto the invention and its mounting in a jet combustion chamber.

The fuel injection device shown in FIGS. 1 and 2 comprises an outerliner 1 and a concentric inner liner 2 defining between them an annularpassage 3 which is traversed, as indicated by the arrows F1, by aircaused to rotate by a swirler 4. A shaped central body or bulb 5defines, together with a concentric liner 6 placed between it and theinner liner 2, a second passage 7 where primary air, flowing in themanner indicated by the arrows F2, is made to rotate by a swirler 8.Fuel reaches the injection device through a nozzle 9 opening into anannular inlet collector 10. The air/fuel mixture flows into the annularspace 11 bounded by the liners 2 and 6, between which is arranged athird swirler 12 ensuring rotation of this air/fuel mixture which flowsin the manner indicated by the arrows F3.

The components referred to above are shown in the exploded view of FIG.3 which illustrates, in a different way, a fuel injection deviceaccording to the invention. The outer passage 3 is effected between theouter liner 1 and the inner liner 2. These two elements areinterconnected by the vanes or blades of the swirler 4. The linerassembly has a cap 13 and at its base it supports a duct 14 for theentry of the air/fuel mixture.

The intermediate passage 11 is defined between the inner liner 2 and theconcentric liner 6, which concentric liner 6 is terminated by a conicalcap 15. The liner 6 supports the swirler l2, composed of helical blades16 and a part-annular rib 17 which diverts part of the air/fuel mixturebefore it reaches the helical blades 16 so as to accelerate rotation ofthe mixture and improve the degree of mixing of the mixture. The innerpassage 7 is defined between the liner 6 and inner bulb 5; the lattercarries the vanes or blades of the swirler 8. The whole device is cappedby a plate 18 which is of such size as to afford a circular slot 19between its inner edge and the cap 13.

The fuel is injected at 9 into the inlet duct 14 which is itself fed byair. The air/fuel mixture then reaches the annular collector 10 andseparates into two streams, the first of which passes directly betweenthe helical blades 16, and the second of which circulates around thehalf rib 17 before reaching the helical blades 16.

The air/fuel mixture is ejected through an annular slot 20 providedbetween the caps 13 and 15. Air caused to rotate by the outer swirler 4emerges through the annular slot 19, whilst the air caused to rotate bythe inner swirler 8 is ejected through a central opening 21.

A fuel injection device as shown in FIGS. 1 and 2 can with advantage beemployed in accordance with the particular method of fitting illustratedin FIG. 4. According to this arrangement, the outer liner 1 forms partof an external sub-assembly A and is screwed directly to the base 22 ofthe combustion chamber. Its rear part comprises a shoulder 23 on whichis welded a thermal screen 24, and its front part carries a thread 25. Athreaded ring 26 fits on the thread 25 and holds the liner 1 tightlyagainst the base of the chamber 22. This liner 1 likewise supports, onits inner face, the swirler 4 and the inner periphery of the swirler 4supports a sleeve 27.

Into this outer sub-assembly A is inserted an inner sub-assembly Bcomprising the liners 2 and 6, the inner swirler 8, the intermediateswirler 12, the central body 5 and the inlet duct 14, within which islocated the nozzle 9 fed with fuel along a passage contained within asupporting arm 28. The sub-assembly B integral with the latter can beintroduced into the housing 29 through a suitable hole 30 which isclosed by a plate 31 forming an integral part of the supporting arm 28and fixed by screws 32 to the housing 29.

The outer swirler 4, which forms part of the subassembly A, is freelymovable relative to the subassembly B, and this facilitates mounting andmaintenance of the device. During operation, the subassembly A is heatedconsiderably and expands, whilst the sub-assembly B is cooled by thecirculation of the air/fuel mixture. The necessary play is provided byrelative sliding movement between the liner 2 and the sleeve 27. Whendismounting, it is merely necessary to remove the screws 32 in order towithdraw the inner sub-assembly B through the hole 30.

We claim:

1. In a multi-swirler fuel injection device to be fitted in a combustionchamber having separate and distinct wall elements (22,29) and of thekind designed to produce an inner air swirl (F2), an outer annular airswirl (F1) around and radially spaced from said inner air swirl, and anintermediate annular air/fuel swirl (F3) sandwiched between said innerand outer air swirls, in

combination, the improvement comprising an assembly including a firstsub-assembly (A) adapted to be secured to one (22) of said wall elementsand comprising an air swirler (4), a second sub-assembly (B) adapted tobe secured to another one (29) of said wall elements and comprisinganother air swirler (8), and guide means (27) mechanically associatedwith said subassemblies for telescoping one into the other in mutallyfitting and relatively slidable relationship.

2. A device as claimed in claim 1, wherein said first sub-assembly (A)comprises the air swirler (4) of said outer annular air swirl (F1), andsaid second subassembly (B) comprises the air swirler (8) of said innerair swirl (F2) and is telescopingly fitted into said first sub-assembly(A).

3. A device as claimed in claim 2, wherein said second sub-assembly (B)further comprises a third swirler (12) associated with said intermediateannular air/fuel swirl (F3).

4. A device as claimed in claim 3, wherein said guide means comprises asleeve (27) located inwardly of the air swirler (4) of said firstsub-assembly (A) and outwardly of the third swirler (12) of said secondsubassembly (B).

5. A device as claimed in claim 4, wherein said sleeve (27) is integralwith said air swirler (4) of said first subassembly (A) and has aslidable fit with said second sub-assembly (B).

6. A device according to claim 1, wherein the blades of the inner andouter swirlers have different angular rotational settings.

7. A device according to claim 6, wherein the angular setting of theouter blades is less than that of the inner blades.

1. In a multi-swirler fuel injection device to be fitted in a combustionchamber having separate and distinct wall elements (22,29) and of thekind designed to produce an inner air swirl (F2), an outer annular airswirl (F1) around and radially spaced from said inner air swirl, and anintermediate annular air/fuel swirl (F3) sandwiched between said innerand outer air swirls, in combination, the improvement comprising anasseMbly including a first sub-assembly (A) adapted to be secured to one(22) of said wall elements and comprising an air swirler (4), a secondsubassembly (B) adapted to be secured to another one (29) of said wallelements and comprising another air swirler (8), and guide means (27)mechanically associated with said sub-assemblies for telescoping oneinto the other in mutally fitting and relatively slidable relationship.2. A device as claimed in claim 1, wherein said first sub-assembly (A)comprises the air swirler (4) of said outer annular air swirl (F1), andsaid second sub-assembly (B) comprises the air swirler (8) of said innerair swirl (F2) and is telescopingly fitted into said first sub-assembly(A).
 3. A device as claimed in claim 2, wherein said second sub-assembly(B) further comprises a third swirler (12) associated with saidintermediate annular air/fuel swirl (F3).
 4. A device as claimed inclaim 3, wherein said guide means comprises a sleeve (27) locatedinwardly of the air swirler (4) of said first sub-assembly (A) andoutwardly of the third swirler (12) of said second sub-assembly (B). 5.A device as claimed in claim 4, wherein said sleeve (27) is integralwith said air swirler (4) of said first sub-assembly (A) and has aslidable fit with said second sub-assembly (B).
 6. A device according toclaim 1, wherein the blades of the inner and outer swirlers havedifferent angular rotational settings.
 7. A device according to claim 6,wherein the angular setting of the outer blades is less than that of theinner blades.